@atomicRmw on u0

[Hejsil]

Under @atomicRmw we have "TODO right now bool is not accepted. Also I think we could make non powers of 2 work fine, maybe we can remove this restriction". If @atomicRmw where to work on u0, then one could write code that is optionally threadsafe without a lot of special casing.

const Lock = if (is_thread_safe) u1 else u0;
const Locked = if (is_thread_safe) 1 else 0;
const Unlocked = 0;

var lock: Lock = Unlocked;
...
// Do @atomicRmw on lock. @atomicRmw will be no-ops on `u0`

Idk if this is a good idea. Maybe @atomicRmw should never be no-op because that might be confusing with its description "This builtin function atomically modifies memory and then returns the previous value.". u0 has no memory to modify.

Related: #1530

[kristate]

You made a very valid point and I think that this is a bad idea to allow. @atomicRmw should never be a noop. I think that this is the nail in the coffin for u0. Integers should be backed by memory -- and they are by definition.

[BarabasGitHub]

I don't see the issue here. It'll write zero and read zero, so it doesn't have to do anything. It just doesn't have any effect. Op di 18 sep. 2018 08:24 schreef kristopher tate <[email protected]>:

…

You made a very valid point and I think that this is a bad idea to allow. @atomicrmw should never be a noop. I think that this is the nail in the coffin for u0. Integers should be backed by memory. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#1549 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AL-sGg_TEb2PJ4IiE1Ax2yCuoEQJN7h-ks5ucJGUgaJpZM4WtOo6> .